EPJ E Highlight - Deflating beach balls and drug delivery

A shell buckles as its internal volume is gradually reduced.

The deflation of beach balls, squash balls and other common objects offers a good model for distortion in microscopic hollow spheres. This can help us understand the properties of some cells and, potentially, develop new drug delivery mechanisms.

Many natural microscopic objects – red blood cells and pollen grains, for example – take the form of distorted spheres. The distortions can be compared to those observed when a sphere is ‘deflated’; so that it steadily loses internal volume. Until now, most of the work done to understand the physics involved has been theoretical. Now, however, Gwennou Coupier and his colleagues at Grenoble Alps University, France have shown that macroscopic-level models of the properties of these tiny spheres agree very well with this theory. The new study, which has implications for targeted drug delivery, was recently published in EPJ E.

Generically, these microscopic objects share their morphology and several other properties with macroscopic thin, spherical shells. Coupier and his team chose to use macroscopic shells as a model because measuring the volumes of and stresses on microscopic shells is extremely challenging from a technical standpoint. Furthermore, macroscopic shells are commercially and quite affordably available. The researchers set up a model system using hollow balls of different sizes and skin thicknesses, ranging from beach balls to squash balls. They were both filled with and submerged in water, and their morphology was observed and pressures measured as some of the water inside was removed.

The apparatus was both simple – it was designed with the help of undergraduate students – and in some ways rather challenging. A manometer used to measure the pressure of 1 atmosphere (the amount of pressure it takes to cause a squash ball to buckle) required a 10-metre-high tube that could only be set up in the lab staircase. The researchers found that the same generic description of buckling that had been predicted theoretically held true in all the varied ‘real-life’ cases tested beyond the range initially expected.

Coupier has found that deflating and inflating microscopic shells can induce directed motion, which could, for example, be used to help target drug delivery to a tumour. He hopes that this new understanding of the mechanics of deflation might allow this motion to be better controlled.

G. Coupier, A. Djellouli and C. Quilliet (2019), Let’s deflate that beach ball, Eur. Phys. J. E 42:129. DOI 10.1140/epje/i2019-11900-2

This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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